This invention relates generally to memory systems, and more particularly to memory systems which are adapted to store a periodic signal and produce complete cycles of such stored periodic signal.
As is known in the art, it is sometimes desirable to receive a pulse of radio frequency energy and produce a continuous wave signal having a frequency related to the frequency of the received energy. Such continuous wave signal may, for example, be transmitted as either a continuous wave signal or may be pulse modulated to enable transmission of a train of radio frequency signals. One technique suggested to produce such continuous wave signal has been to store the received signal in a recirculating memory; however, because the phase of the received signal at the start of the pulse relative to the phase of the signal at the end of the pulse is generally not known because the frequency of the signal is not known, a phase discontinuity distorts the continuous wave signal being produced and thereby reduces the effectiveness of the system. In another technique this phase discontinuity problem is solved by producing control signals indicating the start of each cycle of the received signal. Such technique is described in U.S. Pat. No. 4,223,404, "Apparatus For Recycling Complete Cycles of a Stored Periodic Signal," issued Sept. 16, 1980 to Oscar Lowenschuss and assigned to the same assignee as the present invention. Such system stores either a slice of, or the complete radio frequency pulse, and then recycles complete cycles of the stored signal. While such system is useful in many applications, in other applications it is desirable to recycle complete cycles of a received pulse prior to the termination of either an arbitrary pulse slice thereof or the received pulse itself.